Update aosp/master LLVM for rebase to r222494.

Change-Id: Ic787f5e0124df789bd26f3f24680f45e678eef2d
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
new file mode 100644
index 0000000..2f1b0e5
--- /dev/null
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -0,0 +1,862 @@
+#include "DwarfCompileUnit.h"
+
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Target/TargetFrameLowering.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+namespace llvm {
+
+DwarfCompileUnit::DwarfCompileUnit(unsigned UID, DICompileUnit Node,
+                                   AsmPrinter *A, DwarfDebug *DW,
+                                   DwarfFile *DWU)
+    : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU),
+      Skeleton(nullptr), LabelBegin(nullptr), BaseAddress(nullptr) {
+  insertDIE(Node, &getUnitDie());
+}
+
+/// addLabelAddress - Add a dwarf label attribute data and value using
+/// DW_FORM_addr or DW_FORM_GNU_addr_index.
+///
+void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
+                                       const MCSymbol *Label) {
+
+  // Don't use the address pool in non-fission or in the skeleton unit itself.
+  // FIXME: Once GDB supports this, it's probably worthwhile using the address
+  // pool from the skeleton - maybe even in non-fission (possibly fewer
+  // relocations by sharing them in the pool, but we have other ideas about how
+  // to reduce the number of relocations as well/instead).
+  if (!DD->useSplitDwarf() || !Skeleton)
+    return addLocalLabelAddress(Die, Attribute, Label);
+
+  if (Label)
+    DD->addArangeLabel(SymbolCU(this, Label));
+
+  unsigned idx = DD->getAddressPool().getIndex(Label);
+  DIEValue *Value = new (DIEValueAllocator) DIEInteger(idx);
+  Die.addValue(Attribute, dwarf::DW_FORM_GNU_addr_index, Value);
+}
+
+void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
+                                            dwarf::Attribute Attribute,
+                                            const MCSymbol *Label) {
+  if (Label)
+    DD->addArangeLabel(SymbolCU(this, Label));
+
+  Die.addValue(Attribute, dwarf::DW_FORM_addr,
+               Label ? (DIEValue *)new (DIEValueAllocator) DIELabel(Label)
+                     : new (DIEValueAllocator) DIEInteger(0));
+}
+
+unsigned DwarfCompileUnit::getOrCreateSourceID(StringRef FileName,
+                                               StringRef DirName) {
+  // If we print assembly, we can't separate .file entries according to
+  // compile units. Thus all files will belong to the default compile unit.
+
+  // FIXME: add a better feature test than hasRawTextSupport. Even better,
+  // extend .file to support this.
+  return Asm->OutStreamer.EmitDwarfFileDirective(
+      0, DirName, FileName,
+      Asm->OutStreamer.hasRawTextSupport() ? 0 : getUniqueID());
+}
+
+// Return const expression if value is a GEP to access merged global
+// constant. e.g.
+// i8* getelementptr ({ i8, i8, i8, i8 }* @_MergedGlobals, i32 0, i32 0)
+static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
+  const ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>(V);
+  if (!CE || CE->getNumOperands() != 3 ||
+      CE->getOpcode() != Instruction::GetElementPtr)
+    return nullptr;
+
+  // First operand points to a global struct.
+  Value *Ptr = CE->getOperand(0);
+  if (!isa<GlobalValue>(Ptr) ||
+      !isa<StructType>(cast<PointerType>(Ptr->getType())->getElementType()))
+    return nullptr;
+
+  // Second operand is zero.
+  const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(CE->getOperand(1));
+  if (!CI || !CI->isZero())
+    return nullptr;
+
+  // Third operand is offset.
+  if (!isa<ConstantInt>(CE->getOperand(2)))
+    return nullptr;
+
+  return CE;
+}
+
+/// getOrCreateGlobalVariableDIE - get or create global variable DIE.
+DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(DIGlobalVariable GV) {
+  // Check for pre-existence.
+  if (DIE *Die = getDIE(GV))
+    return Die;
+
+  assert(GV.isGlobalVariable());
+
+  DIScope GVContext = DD->resolve(GV.getContext());
+  DIType GTy = DD->resolve(GV.getType());
+
+  // Construct the context before querying for the existence of the DIE in
+  // case such construction creates the DIE.
+  DIE *ContextDIE = getOrCreateContextDIE(GVContext);
+
+  // Add to map.
+  DIE *VariableDIE = &createAndAddDIE(GV.getTag(), *ContextDIE, GV);
+  DIScope DeclContext;
+
+  if (DIDerivedType SDMDecl = GV.getStaticDataMemberDeclaration()) {
+    DeclContext = resolve(SDMDecl.getContext());
+    assert(SDMDecl.isStaticMember() && "Expected static member decl");
+    assert(GV.isDefinition());
+    // We need the declaration DIE that is in the static member's class.
+    DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
+    addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
+  } else {
+    DeclContext = resolve(GV.getContext());
+    // Add name and type.
+    addString(*VariableDIE, dwarf::DW_AT_name, GV.getDisplayName());
+    addType(*VariableDIE, GTy);
+
+    // Add scoping info.
+    if (!GV.isLocalToUnit())
+      addFlag(*VariableDIE, dwarf::DW_AT_external);
+
+    // Add line number info.
+    addSourceLine(*VariableDIE, GV);
+  }
+
+  if (!GV.isDefinition())
+    addFlag(*VariableDIE, dwarf::DW_AT_declaration);
+
+  // Add location.
+  bool addToAccelTable = false;
+  bool isGlobalVariable = GV.getGlobal() != nullptr;
+  if (isGlobalVariable) {
+    addToAccelTable = true;
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+    const MCSymbol *Sym = Asm->getSymbol(GV.getGlobal());
+    if (GV.getGlobal()->isThreadLocal()) {
+      // FIXME: Make this work with -gsplit-dwarf.
+      unsigned PointerSize = Asm->getDataLayout().getPointerSize();
+      assert((PointerSize == 4 || PointerSize == 8) &&
+             "Add support for other sizes if necessary");
+      // Based on GCC's support for TLS:
+      if (!DD->useSplitDwarf()) {
+        // 1) Start with a constNu of the appropriate pointer size
+        addUInt(*Loc, dwarf::DW_FORM_data1,
+                PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
+        // 2) containing the (relocated) offset of the TLS variable
+        //    within the module's TLS block.
+        addExpr(*Loc, dwarf::DW_FORM_udata,
+                Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
+      } else {
+        addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
+        addUInt(*Loc, dwarf::DW_FORM_udata,
+                DD->getAddressPool().getIndex(Sym, /* TLS */ true));
+      }
+      // 3) followed by a custom OP to make the debugger do a TLS lookup.
+      addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_push_tls_address);
+    } else {
+      DD->addArangeLabel(SymbolCU(this, Sym));
+      addOpAddress(*Loc, Sym);
+    }
+
+    addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
+    // Add the linkage name.
+    StringRef LinkageName = GV.getLinkageName();
+    if (!LinkageName.empty())
+      // From DWARF4: DIEs to which DW_AT_linkage_name may apply include:
+      // TAG_common_block, TAG_constant, TAG_entry_point, TAG_subprogram and
+      // TAG_variable.
+      addString(*VariableDIE,
+                DD->getDwarfVersion() >= 4 ? dwarf::DW_AT_linkage_name
+                                           : dwarf::DW_AT_MIPS_linkage_name,
+                GlobalValue::getRealLinkageName(LinkageName));
+  } else if (const ConstantInt *CI =
+                 dyn_cast_or_null<ConstantInt>(GV.getConstant())) {
+    addConstantValue(*VariableDIE, CI, GTy);
+  } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV.getConstant())) {
+    addToAccelTable = true;
+    // GV is a merged global.
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+    Value *Ptr = CE->getOperand(0);
+    MCSymbol *Sym = Asm->getSymbol(cast<GlobalValue>(Ptr));
+    DD->addArangeLabel(SymbolCU(this, Sym));
+    addOpAddress(*Loc, Sym);
+    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
+    SmallVector<Value *, 3> Idx(CE->op_begin() + 1, CE->op_end());
+    addUInt(*Loc, dwarf::DW_FORM_udata,
+            Asm->getDataLayout().getIndexedOffset(Ptr->getType(), Idx));
+    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
+    addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
+  }
+
+  if (addToAccelTable) {
+    DD->addAccelName(GV.getName(), *VariableDIE);
+
+    // If the linkage name is different than the name, go ahead and output
+    // that as well into the name table.
+    if (GV.getLinkageName() != "" && GV.getName() != GV.getLinkageName())
+      DD->addAccelName(GV.getLinkageName(), *VariableDIE);
+  }
+
+  addGlobalName(GV.getName(), *VariableDIE, DeclContext);
+  return VariableDIE;
+}
+
+void DwarfCompileUnit::addRange(RangeSpan Range) {
+  bool SameAsPrevCU = this == DD->getPrevCU();
+  DD->setPrevCU(this);
+  // If we have no current ranges just add the range and return, otherwise,
+  // check the current section and CU against the previous section and CU we
+  // emitted into and the subprogram was contained within. If these are the
+  // same then extend our current range, otherwise add this as a new range.
+  if (CURanges.empty() || !SameAsPrevCU ||
+      (&CURanges.back().getEnd()->getSection() !=
+       &Range.getEnd()->getSection())) {
+    CURanges.push_back(Range);
+    return;
+  }
+
+  CURanges.back().setEnd(Range.getEnd());
+}
+
+void DwarfCompileUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
+                                       const MCSymbol *Label,
+                                       const MCSymbol *Sec) {
+  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
+    addLabel(Die, Attribute,
+             DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+                                        : dwarf::DW_FORM_data4,
+             Label);
+  else
+    addSectionDelta(Die, Attribute, Label, Sec);
+}
+
+void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {
+  // Define start line table label for each Compile Unit.
+  MCSymbol *LineTableStartSym =
+      Asm->OutStreamer.getDwarfLineTableSymbol(getUniqueID());
+
+  stmtListIndex = UnitDie.getValues().size();
+
+  // DW_AT_stmt_list is a offset of line number information for this
+  // compile unit in debug_line section. For split dwarf this is
+  // left in the skeleton CU and so not included.
+  // The line table entries are not always emitted in assembly, so it
+  // is not okay to use line_table_start here.
+  addSectionLabel(UnitDie, dwarf::DW_AT_stmt_list, LineTableStartSym,
+                  DwarfLineSectionSym);
+}
+
+void DwarfCompileUnit::applyStmtList(DIE &D) {
+  D.addValue(dwarf::DW_AT_stmt_list,
+             UnitDie.getAbbrev().getData()[stmtListIndex].getForm(),
+             UnitDie.getValues()[stmtListIndex]);
+}
+
+void DwarfCompileUnit::attachLowHighPC(DIE &D, const MCSymbol *Begin,
+                                       const MCSymbol *End) {
+  assert(Begin && "Begin label should not be null!");
+  assert(End && "End label should not be null!");
+  assert(Begin->isDefined() && "Invalid starting label");
+  assert(End->isDefined() && "Invalid end label");
+
+  addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
+  if (DD->getDwarfVersion() < 4)
+    addLabelAddress(D, dwarf::DW_AT_high_pc, End);
+  else
+    addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
+}
+
+// Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
+// and DW_AT_high_pc attributes. If there are global variables in this
+// scope then create and insert DIEs for these variables.
+DIE &DwarfCompileUnit::updateSubprogramScopeDIE(DISubprogram SP) {
+  DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
+
+  attachLowHighPC(*SPDie, DD->getFunctionBeginSym(), DD->getFunctionEndSym());
+  if (!DD->getCurrentFunction()->getTarget().Options.DisableFramePointerElim(
+          *DD->getCurrentFunction()))
+    addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
+
+  // Only include DW_AT_frame_base in full debug info
+  if (!includeMinimalInlineScopes()) {
+    const TargetRegisterInfo *RI =
+        Asm->TM.getSubtargetImpl()->getRegisterInfo();
+    MachineLocation Location(RI->getFrameRegister(*Asm->MF));
+    addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
+  }
+
+  // Add name to the name table, we do this here because we're guaranteed
+  // to have concrete versions of our DW_TAG_subprogram nodes.
+  DD->addSubprogramNames(SP, *SPDie);
+
+  return *SPDie;
+}
+
+// Construct a DIE for this scope.
+void DwarfCompileUnit::constructScopeDIE(
+    LexicalScope *Scope, SmallVectorImpl<std::unique_ptr<DIE>> &FinalChildren) {
+  if (!Scope || !Scope->getScopeNode())
+    return;
+
+  DIScope DS(Scope->getScopeNode());
+
+  assert((Scope->getInlinedAt() || !DS.isSubprogram()) &&
+         "Only handle inlined subprograms here, use "
+         "constructSubprogramScopeDIE for non-inlined "
+         "subprograms");
+
+  SmallVector<std::unique_ptr<DIE>, 8> Children;
+
+  // We try to create the scope DIE first, then the children DIEs. This will
+  // avoid creating un-used children then removing them later when we find out
+  // the scope DIE is null.
+  std::unique_ptr<DIE> ScopeDIE;
+  if (Scope->getParent() && DS.isSubprogram()) {
+    ScopeDIE = constructInlinedScopeDIE(Scope);
+    if (!ScopeDIE)
+      return;
+    // We create children when the scope DIE is not null.
+    createScopeChildrenDIE(Scope, Children);
+  } else {
+    // Early exit when we know the scope DIE is going to be null.
+    if (DD->isLexicalScopeDIENull(Scope))
+      return;
+
+    unsigned ChildScopeCount;
+
+    // We create children here when we know the scope DIE is not going to be
+    // null and the children will be added to the scope DIE.
+    createScopeChildrenDIE(Scope, Children, &ChildScopeCount);
+
+    // Skip imported directives in gmlt-like data.
+    if (!includeMinimalInlineScopes()) {
+      // There is no need to emit empty lexical block DIE.
+      for (const auto &E : DD->findImportedEntitiesForScope(DS))
+        Children.push_back(
+            constructImportedEntityDIE(DIImportedEntity(E.second)));
+    }
+
+    // If there are only other scopes as children, put them directly in the
+    // parent instead, as this scope would serve no purpose.
+    if (Children.size() == ChildScopeCount) {
+      FinalChildren.insert(FinalChildren.end(),
+                           std::make_move_iterator(Children.begin()),
+                           std::make_move_iterator(Children.end()));
+      return;
+    }
+    ScopeDIE = constructLexicalScopeDIE(Scope);
+    assert(ScopeDIE && "Scope DIE should not be null.");
+  }
+
+  // Add children
+  for (auto &I : Children)
+    ScopeDIE->addChild(std::move(I));
+
+  FinalChildren.push_back(std::move(ScopeDIE));
+}
+
+void DwarfCompileUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
+                                       const MCSymbol *Hi, const MCSymbol *Lo) {
+  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
+  Die.addValue(Attribute, DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+                                                     : dwarf::DW_FORM_data4,
+               Value);
+}
+
+void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
+                                         SmallVector<RangeSpan, 2> Range) {
+  // Emit offset in .debug_range as a relocatable label. emitDIE will handle
+  // emitting it appropriately.
+  auto *RangeSectionSym = DD->getRangeSectionSym();
+
+  RangeSpanList List(
+      Asm->GetTempSymbol("debug_ranges", DD->getNextRangeNumber()),
+      std::move(Range));
+
+  // Under fission, ranges are specified by constant offsets relative to the
+  // CU's DW_AT_GNU_ranges_base.
+  if (isDwoUnit())
+    addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
+                    RangeSectionSym);
+  else
+    addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
+                    RangeSectionSym);
+
+  // Add the range list to the set of ranges to be emitted.
+  (Skeleton ? Skeleton : this)->CURangeLists.push_back(std::move(List));
+}
+
+void DwarfCompileUnit::attachRangesOrLowHighPC(
+    DIE &Die, SmallVector<RangeSpan, 2> Ranges) {
+  if (Ranges.size() == 1) {
+    const auto &single = Ranges.front();
+    attachLowHighPC(Die, single.getStart(), single.getEnd());
+  } else
+    addScopeRangeList(Die, std::move(Ranges));
+}
+
+void DwarfCompileUnit::attachRangesOrLowHighPC(
+    DIE &Die, const SmallVectorImpl<InsnRange> &Ranges) {
+  SmallVector<RangeSpan, 2> List;
+  List.reserve(Ranges.size());
+  for (const InsnRange &R : Ranges)
+    List.push_back(RangeSpan(DD->getLabelBeforeInsn(R.first),
+                             DD->getLabelAfterInsn(R.second)));
+  attachRangesOrLowHighPC(Die, std::move(List));
+}
+
+// This scope represents inlined body of a function. Construct DIE to
+// represent this concrete inlined copy of the function.
+std::unique_ptr<DIE>
+DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
+  assert(Scope->getScopeNode());
+  DIScope DS(Scope->getScopeNode());
+  DISubprogram InlinedSP = getDISubprogram(DS);
+  // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
+  // was inlined from another compile unit.
+  DIE *OriginDIE = DU->getAbstractSPDies()[InlinedSP];
+  assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
+
+  auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_inlined_subroutine);
+  addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
+
+  attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
+
+  // Add the call site information to the DIE.
+  DILocation DL(Scope->getInlinedAt());
+  addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
+          getOrCreateSourceID(DL.getFilename(), DL.getDirectory()));
+  addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, DL.getLineNumber());
+
+  // Add name to the name table, we do this here because we're guaranteed
+  // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
+  DD->addSubprogramNames(InlinedSP, *ScopeDIE);
+
+  return ScopeDIE;
+}
+
+// Construct new DW_TAG_lexical_block for this scope and attach
+// DW_AT_low_pc/DW_AT_high_pc labels.
+std::unique_ptr<DIE>
+DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
+  if (DD->isLexicalScopeDIENull(Scope))
+    return nullptr;
+
+  auto ScopeDIE = make_unique<DIE>(dwarf::DW_TAG_lexical_block);
+  if (Scope->isAbstractScope())
+    return ScopeDIE;
+
+  attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
+
+  return ScopeDIE;
+}
+
+/// constructVariableDIE - Construct a DIE for the given DbgVariable.
+std::unique_ptr<DIE> DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
+                                                            bool Abstract) {
+  auto D = constructVariableDIEImpl(DV, Abstract);
+  DV.setDIE(*D);
+  return D;
+}
+
+std::unique_ptr<DIE>
+DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
+                                           bool Abstract) {
+  // Define variable debug information entry.
+  auto VariableDie = make_unique<DIE>(DV.getTag());
+
+  if (Abstract) {
+    applyVariableAttributes(DV, *VariableDie);
+    return VariableDie;
+  }
+
+  // Add variable address.
+
+  unsigned Offset = DV.getDotDebugLocOffset();
+  if (Offset != ~0U) {
+    addLocationList(*VariableDie, dwarf::DW_AT_location, Offset);
+    return VariableDie;
+  }
+
+  // Check if variable is described by a DBG_VALUE instruction.
+  if (const MachineInstr *DVInsn = DV.getMInsn()) {
+    assert(DVInsn->getNumOperands() == 4);
+    if (DVInsn->getOperand(0).isReg()) {
+      const MachineOperand RegOp = DVInsn->getOperand(0);
+      // If the second operand is an immediate, this is an indirect value.
+      if (DVInsn->getOperand(1).isImm()) {
+        MachineLocation Location(RegOp.getReg(),
+                                 DVInsn->getOperand(1).getImm());
+        addVariableAddress(DV, *VariableDie, Location);
+      } else if (RegOp.getReg())
+        addVariableAddress(DV, *VariableDie, MachineLocation(RegOp.getReg()));
+    } else if (DVInsn->getOperand(0).isImm())
+      addConstantValue(*VariableDie, DVInsn->getOperand(0), DV.getType());
+    else if (DVInsn->getOperand(0).isFPImm())
+      addConstantFPValue(*VariableDie, DVInsn->getOperand(0));
+    else if (DVInsn->getOperand(0).isCImm())
+      addConstantValue(*VariableDie, DVInsn->getOperand(0).getCImm(),
+                       DV.getType());
+
+    return VariableDie;
+  }
+
+  // .. else use frame index.
+  int FI = DV.getFrameIndex();
+  if (FI != ~0) {
+    unsigned FrameReg = 0;
+    const TargetFrameLowering *TFI =
+        Asm->TM.getSubtargetImpl()->getFrameLowering();
+    int Offset = TFI->getFrameIndexReference(*Asm->MF, FI, FrameReg);
+    MachineLocation Location(FrameReg, Offset);
+    addVariableAddress(DV, *VariableDie, Location);
+  }
+
+  return VariableDie;
+}
+
+std::unique_ptr<DIE> DwarfCompileUnit::constructVariableDIE(
+    DbgVariable &DV, const LexicalScope &Scope, DIE *&ObjectPointer) {
+  auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
+  if (DV.isObjectPointer())
+    ObjectPointer = Var.get();
+  return Var;
+}
+
+DIE *DwarfCompileUnit::createScopeChildrenDIE(
+    LexicalScope *Scope, SmallVectorImpl<std::unique_ptr<DIE>> &Children,
+    unsigned *ChildScopeCount) {
+  DIE *ObjectPointer = nullptr;
+
+  for (DbgVariable *DV : DU->getScopeVariables().lookup(Scope))
+    Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
+
+  unsigned ChildCountWithoutScopes = Children.size();
+
+  for (LexicalScope *LS : Scope->getChildren())
+    constructScopeDIE(LS, Children);
+
+  if (ChildScopeCount)
+    *ChildScopeCount = Children.size() - ChildCountWithoutScopes;
+
+  return ObjectPointer;
+}
+
+void DwarfCompileUnit::constructSubprogramScopeDIE(LexicalScope *Scope) {
+  assert(Scope && Scope->getScopeNode());
+  assert(!Scope->getInlinedAt());
+  assert(!Scope->isAbstractScope());
+  DISubprogram Sub(Scope->getScopeNode());
+
+  assert(Sub.isSubprogram());
+
+  DD->getProcessedSPNodes().insert(Sub);
+
+  DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
+
+  // If this is a variadic function, add an unspecified parameter.
+  DITypeArray FnArgs = Sub.getType().getTypeArray();
+
+  // Collect lexical scope children first.
+  // ObjectPointer might be a local (non-argument) local variable if it's a
+  // block's synthetic this pointer.
+  if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, ScopeDIE))
+    addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
+
+  // If we have a single element of null, it is a function that returns void.
+  // If we have more than one elements and the last one is null, it is a
+  // variadic function.
+  if (FnArgs.getNumElements() > 1 &&
+      !FnArgs.getElement(FnArgs.getNumElements() - 1) &&
+      !includeMinimalInlineScopes())
+    ScopeDIE.addChild(make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
+}
+
+DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
+                                                 DIE &ScopeDIE) {
+  // We create children when the scope DIE is not null.
+  SmallVector<std::unique_ptr<DIE>, 8> Children;
+  DIE *ObjectPointer = createScopeChildrenDIE(Scope, Children);
+
+  // Add children
+  for (auto &I : Children)
+    ScopeDIE.addChild(std::move(I));
+
+  return ObjectPointer;
+}
+
+void
+DwarfCompileUnit::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) {
+  DIE *&AbsDef = DU->getAbstractSPDies()[Scope->getScopeNode()];
+  if (AbsDef)
+    return;
+
+  DISubprogram SP(Scope->getScopeNode());
+
+  DIE *ContextDIE;
+
+  if (includeMinimalInlineScopes())
+    ContextDIE = &getUnitDie();
+  // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
+  // the important distinction that the DIDescriptor is not associated with the
+  // DIE (since the DIDescriptor will be associated with the concrete DIE, if
+  // any). It could be refactored to some common utility function.
+  else if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
+    ContextDIE = &getUnitDie();
+    getOrCreateSubprogramDIE(SPDecl);
+  } else
+    ContextDIE = getOrCreateContextDIE(resolve(SP.getContext()));
+
+  // Passing null as the associated DIDescriptor because the abstract definition
+  // shouldn't be found by lookup.
+  AbsDef =
+      &createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, DIDescriptor());
+  applySubprogramAttributesToDefinition(SP, *AbsDef);
+
+  if (!includeMinimalInlineScopes())
+    addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
+  if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, *AbsDef))
+    addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
+}
+
+std::unique_ptr<DIE>
+DwarfCompileUnit::constructImportedEntityDIE(const DIImportedEntity &Module) {
+  assert(Module.Verify() &&
+         "Use one of the MDNode * overloads to handle invalid metadata");
+  std::unique_ptr<DIE> IMDie = make_unique<DIE>((dwarf::Tag)Module.getTag());
+  insertDIE(Module, IMDie.get());
+  DIE *EntityDie;
+  DIDescriptor Entity = resolve(Module.getEntity());
+  if (Entity.isNameSpace())
+    EntityDie = getOrCreateNameSpace(DINameSpace(Entity));
+  else if (Entity.isSubprogram())
+    EntityDie = getOrCreateSubprogramDIE(DISubprogram(Entity));
+  else if (Entity.isType())
+    EntityDie = getOrCreateTypeDIE(DIType(Entity));
+  else if (Entity.isGlobalVariable())
+    EntityDie = getOrCreateGlobalVariableDIE(DIGlobalVariable(Entity));
+  else
+    EntityDie = getDIE(Entity);
+  assert(EntityDie);
+  addSourceLine(*IMDie, Module.getLineNumber(),
+                Module.getContext().getFilename(),
+                Module.getContext().getDirectory());
+  addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
+  StringRef Name = Module.getName();
+  if (!Name.empty())
+    addString(*IMDie, dwarf::DW_AT_name, Name);
+
+  return IMDie;
+}
+
+void DwarfCompileUnit::finishSubprogramDefinition(DISubprogram SP) {
+  DIE *D = getDIE(SP);
+  if (DIE *AbsSPDIE = DU->getAbstractSPDies().lookup(SP)) {
+    if (D)
+      // If this subprogram has an abstract definition, reference that
+      addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
+  } else {
+    if (!D && !includeMinimalInlineScopes())
+      // Lazily construct the subprogram if we didn't see either concrete or
+      // inlined versions during codegen. (except in -gmlt ^ where we want
+      // to omit these entirely)
+      D = getOrCreateSubprogramDIE(SP);
+    if (D)
+      // And attach the attributes
+      applySubprogramAttributesToDefinition(SP, *D);
+  }
+}
+void DwarfCompileUnit::collectDeadVariables(DISubprogram SP) {
+  assert(SP.isSubprogram() && "CU's subprogram list contains a non-subprogram");
+  assert(SP.isDefinition() &&
+         "CU's subprogram list contains a subprogram declaration");
+  DIArray Variables = SP.getVariables();
+  if (Variables.getNumElements() == 0)
+    return;
+
+  DIE *SPDIE = DU->getAbstractSPDies().lookup(SP);
+  if (!SPDIE)
+    SPDIE = getDIE(SP);
+  assert(SPDIE);
+  for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
+    DIVariable DV(Variables.getElement(vi));
+    assert(DV.isVariable());
+    DbgVariable NewVar(DV, DIExpression(nullptr), DD);
+    auto VariableDie = constructVariableDIE(NewVar);
+    applyVariableAttributes(NewVar, *VariableDie);
+    SPDIE->addChild(std::move(VariableDie));
+  }
+}
+
+void DwarfCompileUnit::emitHeader(const MCSymbol *ASectionSym) const {
+  // Don't bother labeling the .dwo unit, as its offset isn't used.
+  if (!Skeleton)
+    Asm->OutStreamer.EmitLabel(LabelBegin);
+
+  DwarfUnit::emitHeader(ASectionSym);
+}
+
+/// addGlobalName - Add a new global name to the compile unit.
+void DwarfCompileUnit::addGlobalName(StringRef Name, DIE &Die,
+                                     DIScope Context) {
+  if (includeMinimalInlineScopes())
+    return;
+  std::string FullName = getParentContextString(Context) + Name.str();
+  GlobalNames[FullName] = &Die;
+}
+
+/// Add a new global type to the unit.
+void DwarfCompileUnit::addGlobalType(DIType Ty, const DIE &Die,
+                                     DIScope Context) {
+  if (includeMinimalInlineScopes())
+    return;
+  std::string FullName = getParentContextString(Context) + Ty.getName().str();
+  GlobalTypes[FullName] = &Die;
+}
+
+/// addVariableAddress - Add DW_AT_location attribute for a
+/// DbgVariable based on provided MachineLocation.
+void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
+                                          MachineLocation Location) {
+  if (DV.variableHasComplexAddress())
+    addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
+  else if (DV.isBlockByrefVariable())
+    addBlockByrefAddress(DV, Die, dwarf::DW_AT_location, Location);
+  else
+    addAddress(Die, dwarf::DW_AT_location, Location,
+               DV.getVariable().isIndirect());
+}
+
+/// Add an address attribute to a die based on the location provided.
+void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
+                                  const MachineLocation &Location,
+                                  bool Indirect) {
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+
+  if (Location.isReg() && !Indirect)
+    addRegisterOpPiece(*Loc, Location.getReg());
+  else {
+    addRegisterOffset(*Loc, Location.getReg(), Location.getOffset());
+    if (Indirect && !Location.isReg()) {
+      addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+    }
+  }
+
+  // Now attach the location information to the DIE.
+  addBlock(Die, Attribute, Loc);
+}
+
+/// Start with the address based on the location provided, and generate the
+/// DWARF information necessary to find the actual variable given the extra
+/// address information encoded in the DbgVariable, starting from the starting
+/// location.  Add the DWARF information to the die.
+void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
+                                         dwarf::Attribute Attribute,
+                                         const MachineLocation &Location) {
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+  unsigned N = DV.getNumAddrElements();
+  unsigned i = 0;
+  if (Location.isReg()) {
+    if (N >= 2 && DV.getAddrElement(0) == dwarf::DW_OP_plus) {
+      assert(!DV.getVariable().isIndirect() &&
+             "double indirection not handled");
+      // If first address element is OpPlus then emit
+      // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
+      addRegisterOffset(*Loc, Location.getReg(), DV.getAddrElement(1));
+      i = 2;
+    } else if (N >= 2 && DV.getAddrElement(0) == dwarf::DW_OP_deref) {
+      assert(!DV.getVariable().isIndirect() &&
+             "double indirection not handled");
+      addRegisterOpPiece(*Loc, Location.getReg(),
+                         DV.getExpression().getPieceSize(),
+                         DV.getExpression().getPieceOffset());
+      i = 3;
+    } else
+      addRegisterOpPiece(*Loc, Location.getReg());
+  } else
+    addRegisterOffset(*Loc, Location.getReg(), Location.getOffset());
+
+  for (; i < N; ++i) {
+    uint64_t Element = DV.getAddrElement(i);
+    if (Element == dwarf::DW_OP_plus) {
+      addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
+      addUInt(*Loc, dwarf::DW_FORM_udata, DV.getAddrElement(++i));
+
+    } else if (Element == dwarf::DW_OP_deref) {
+      if (!Location.isReg())
+        addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+
+    } else if (Element == dwarf::DW_OP_piece) {
+      const unsigned SizeOfByte = 8;
+      unsigned PieceOffsetInBits = DV.getAddrElement(++i) * SizeOfByte;
+      unsigned PieceSizeInBits = DV.getAddrElement(++i) * SizeOfByte;
+      // Emit DW_OP_bit_piece Size Offset.
+      assert(PieceSizeInBits > 0 && "piece has zero size");
+      addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_bit_piece);
+      addUInt(*Loc, dwarf::DW_FORM_udata, PieceSizeInBits);
+      addUInt(*Loc, dwarf::DW_FORM_udata, PieceOffsetInBits);
+    } else
+      llvm_unreachable("unknown DIBuilder Opcode");
+  }
+
+  // Now attach the location information to the DIE.
+  addBlock(Die, Attribute, Loc);
+}
+
+/// Add a Dwarf loclistptr attribute data and value.
+void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
+                                       unsigned Index) {
+  DIEValue *Value = new (DIEValueAllocator) DIELocList(Index);
+  dwarf::Form Form = DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+                                                : dwarf::DW_FORM_data4;
+  Die.addValue(Attribute, Form, Value);
+}
+
+void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
+                                               DIE &VariableDie) {
+  StringRef Name = Var.getName();
+  if (!Name.empty())
+    addString(VariableDie, dwarf::DW_AT_name, Name);
+  addSourceLine(VariableDie, Var.getVariable());
+  addType(VariableDie, Var.getType());
+  if (Var.isArtificial())
+    addFlag(VariableDie, dwarf::DW_AT_artificial);
+}
+
+/// Add a Dwarf expression attribute data and value.
+void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
+                               const MCExpr *Expr) {
+  DIEValue *Value = new (DIEValueAllocator) DIEExpr(Expr);
+  Die.addValue((dwarf::Attribute)0, Form, Value);
+}
+
+void DwarfCompileUnit::applySubprogramAttributesToDefinition(DISubprogram SP,
+                                                             DIE &SPDie) {
+  DISubprogram SPDecl = SP.getFunctionDeclaration();
+  DIScope Context = resolve(SPDecl ? SPDecl.getContext() : SP.getContext());
+  applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
+  addGlobalName(SP.getName(), SPDie, Context);
+}
+
+bool DwarfCompileUnit::isDwoUnit() const {
+  return DD->useSplitDwarf() && Skeleton;
+}
+
+bool DwarfCompileUnit::includeMinimalInlineScopes() const {
+  return getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly ||
+         (DD->useSplitDwarf() && !Skeleton);
+}
+} // end llvm namespace